A new analysis suggests North Korea clandestinely tested two nuclear weapons in 2010. If it's true, it would double the number of known tests hailing from the country and could mean serious nuclear warhead development is underway.

Remember when North Korea made that bizarre claim in May 2010 that they had achieved nuclear fusion? This might explain why. Western media mocked the announcement, but a small circle of experts who do nothing but hunt for covert nuclear tests were worried for real. Nature reports that "South Korean scientists had detected a whiff of radioactive xenon at around that time, hinting at nuclear activity in its northern neighbour."

Yesterday, North Korea's official state media reported that the country had successfully…
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One of the nuke hunters is Lars-Erik De Geer, an atmospheric scientist at the Swedish Defence Research Agency in Stockholm. After analyzing data from Russian and Japanese stations close to North Korea, he concluded: "Hell, we cannot explain them."

De Geer spent the next year studying everything he could find relating to that time period, and concludes that North Korea performed two small nuclear tests in April and May 2010, with the goal of building a more powerful bomb. He's publishing his study in the April/May issue of the journal Science and Global Security.

Here's what he found: ratios of xenon-133 and xenon-133m indicate an explosion in mid-April, and ratios of barium-140 and its radioactive decay product lanthanum-140 point to a second test around 11 May. Barium-140 can be explained only by a sudden nuclear event, De Geer says, and ratios of other xenon isotopes indicate a fast nuclear reaction that involved uranium.

The potential tests come on the heels of two confirmed North Korea nuclear weapon dabblings in 2006 and 2009. And South Korean officials just last year announced last year that their northern neighbors were close to developing a nuclear missile. But while the intent is clear and the evidence strong, it's still not entirely certain that what was being recorded was the result of a weapons test.

According to South Korea's defense minister, North Korea may have created a nuclear warhead…
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The resulting explosions would have felt like 50 to 200 tons of TNT exploding. And that's what's making other scientists skeptical. No seismic vibrations were recorded at the time, and the Korean peninsula is wired to detect the tiniest shakes, according to Ola Dahlman, a retired geophysicist who spent much of his career working with the Comprehensive Nuclear Test Ban Treaty, an unratified treaty that seeks to ban all nuclear explosions. Other scientist agree that more data is necessary to confirm De Geer's findings.

Let's sincerely hope that Kim Jong Un won't follow in his father's footsteps, and will worry more about feeding his starving citizens than defying worldwide condemnation to build nuclear weapons. [Nature]